L-acylamnoaryl-s-pyrazolones



. known Patented June 29, 1943 UNITED STATES PATENT OFFICE v1-ACY A INORYL-s-rizimzoLomis Paul Zervas, Cologne Mulheim, Germany, assignertoGeneral Aniline & Film Corporation,

New .York, N. Y., a corporation of Delaware No Drawing. ApplicationAugust 9, 1941, Serial No. 406,242. In Germany January 29, 1940 (Cl.260-310) The present invention relates to l-acylamino- 8 Claims.

aryl--pyrazolones and to a method of Preparing the same. h

It is known that 1-(4'-acetylaminophenyl) -3- methyl-5-pyrazolone can beprepared by reacting 4-acetylaminophenylhydrazine with excessacetoacetic ester at about 150 C. It is 'further that1-(4T-benzoylaminophenyl) -3- methyl-5-pyrazolone can be'prepared by theinteraction of the hydrazine of p-benzoylphenylenediamine with excess(about 50 per cent) aceto-" acetic ester in glacial acetic acid and inthe presence of sodium acetate. Also the preparation of the urea of the1-(3'-aminophenyl) -3 -methyl- E-pyrazolone is known; this urea isobtained by passing phosgene into the solution of the pythe 4-positionis split ofi, whereas the acylamino groups are not saponified. V

The acylaminoaryl-5-pyrazo1ones thus obtained which are new apart fromthe few exceptions mentioned above are valuable intermediates for theproduction of dyestuffs.

The acids used as starting materials are, in general, obtainableaccording to the above mentioned copending application by reacting theamino group of 1-aminoaryl-5-pyrazolone-4-sulfonic acids with organiccompounds containing one or more replaceable halogen groups. As suitablecompounds containing one or more replaceable halogen groups may be used,e. g., phosgene, monoand dicarboxylic acid chlorides. The condensationis effected in aqueous medium at an alkaline to weakly acid reaction.The method of producing the starting materials is only given asillustrative, and applicants process is not intended to be limited tothe treatment of l-acylaminoaryl-5-pyrazolone-4-sulfonic acids obtainedonly by the method described in the aforementioned co-pendingapplication.

The following examples illustrate theinvenl-acylaminoaryl-5-pyrazolone-4-sulfonic" stirred for some time.

tion without, however, limiting it thereto, the parts being by weight.

Example 1 100 parts of 1-(3'-benzoylaminophenyl) -3-methyl-5-pyrazolone-4-sulfonic acid are added to 850 parts of sulfuricacid of Be. in such manner that the temperature does not rise above 50C. The, mixture is now heated for one hour to 55-57 0. whereby a clearsolution is formed. In order to isolate the reaction product the acidsolution is poured on ice and the separated l-(3-benzoylaminophenyl)-3-methyl-5-pyrazolone is filtered with suction.Yield about per cent.

If the 1-(4'-benzoylaminophenyl)-3-methyl 5-pyrazolone-4-sulfonic acidor the 1- (3-benzoylaminophenyl) -5-pyrazolone-3-carboxy1icacid-isulfonic acid is used instead of the l-(3-benzoylaminophenyl)-3emethyl-B-pyrazolona4-sulfonic acid the corresponding pyrazolonederivatives are obtained with the same good yield.

Emample 2 500 parts of an about 43 per cent paste of LE3- (3-nitrobenzoylamino) -phenyll -5 pyrazolone- 3-carboxylic acid 4-sulfonicacid are gradually added to 2000 parts of sulfuric acid of 60 Be. insuch manner that the temperature does not rise above 50 C. The pastedissolves after being In order to completely split off the sulfonic acidgroup the mixture is heated for one hour to 55 C. After cooling the acidsolution is poured on 1700 parts of ice and the separated 1- [3"- (3"-nitrobenzoylarhino) phenyl]-5-pyraz01one-3-carboxylic acid is filteredwith suction. Yield about 90 per cent.

It the 1-[3'-(4-nitrobenzoylamino) -phenyllfi-pyrazolone-B-carboxylicacid-4-sulfonic acid or the 1- [4' (4 '-nitrobenzoylamino) -phenyl] -3-methyl-5-pyrazolone-4-sulfonic acid is used instead of the l-[3'-(3"-nitrobenzoylamino)- phenyl]-5-pyrazo1one-3-carboxylicacid--sulfonic acid the corresponding pyrazolone derivatives areobtained with the same good yield.

Example 3 500 parts of an about 40 per cent paste of1-[4-(4-amin0benz0ylamin0) p h e n yl] 3 methyl-5-pyrazolone-4-sulfonioacid are added to 3000 parts of sulfuric acid of 60 B. in the mannerdescribed in Example 2. The mixture is stirred for 2 hours until itdissolves at 5052 C. and poured on ice whereby the1[4-(4-aminobenzoylamino) -phenyl]-3-methyl 5 pyrazolone separates witha yield of to per cent.

(4' -aminobenzoylamino) -phenyl] -5-pyrazolone- S-carboxylicacidl-sulfonic acid.

Example 4 300 parts of an about 35 per cent paste of the condensationproduct obtained from 1-(4'-aminophenyl)-3-methy1-5-pyraz01one 4sulfonic acid and phosgene are added to 1600 parts of sulfuric acid of60 B. and heated to 55-5'7" C. for one hour. The acid solution isworkedup in the manner stated in Example 1 whereby the pyrazolone derivativeof the following constitution HaC.C=N\ /N=C.CH3

N- NH.CO.NH N C O H2 CO-bHz is formed with a yield of about 80 per cent.

Example 5 100 parts of the condensation product obtained from1-(4-aminophenyl) -3-methyl- 5-pyrazolone-4-sulfonic acid and.benzene-1.4-

acids with strong sulfuric acid at a sufliciently elevated temperatureat which the 4-sulfonic acid group splits ofi.

2. Process of preparing l-acylamino-phenyl- 5-pyrazo10nes whichcomprises splitting ofi the 4-sulfonic acid group of1-acylamino-phenyl-5- pyrazolone-4-sulfonic acids by treating theseacids with strong sulfuric acid at temperatures of about 40 C. to about60 C.

3. Process of preparing l-aroylamino-phenyl- 5-pyrazolones whichcomprises splitting off the 4-sulfonic acid group of1-aroylamino-phenyl-5- pyrazolonel-sulfonic acids by treating theseacids with strong sulfuric acid at temperatures of about 40 C. to about60 C.

4. Process of preparing l-nitrobenzoylaminophenyl-5-pyrazolones whichcomprises splitting off the 4-su1fonic acid group of l-nitrobenzoyl- Iaminophenyl-5-pyrazolone-4-su1fonic acids by dicarboxylic acid chlorideare added to 680 parts v of sulfuric acid of 60 B., heated according toExample 1 and the reaction product is isolated with a yield of about70-75 per cent by pouring the mixture on ice. The pyrazolone derivativethus obtained possesses the following constitutreating these acids withstrong sulfonic acid at temperatures of about C. to about 60 C.

5. Process of preparing 1-[3-(3"-nitrobenzoylamino)-phenyl]-5-pyrazolone-3 carboxylic acid which comprises splitting offthe 4-su1fonic acid of 1-[3'-(3"-nitrobenzoylamino) -pheny1]-5-pyrazolone-3-carboxylic acid-4-su1fonic acid group by treating thisacid with strong sulfuric acid at about C. to about C.

6. Process of preparing l-a'minobenzoylaminophenyl-B-pyrazolones whichcomprises splitting off the 4-sulfonic acid group ofl-aminobenzoylaminophenyl-5-pyrazolone-4-sulfonic acids by treatingthese acids with strong sulfuric acid at temperatures of about 40 C. toabout C.

7. Process of preparing 1-[4'-(4-aminobenz- Example 6 parts of1-(4-acetylaminophenyl) -3- methyl-5-pyrazolone-4=-sulfonic acid areadded oylamino)-phenyll 3 methyl 5 pyrazolone which comprises splittingoff the 4-sul'fonic acid to 500 parts of sulfuric acid of 60 B. in sucha manner that the temperature does not rise above 40 C. The mixture isthen heated for one hour to 45-50" C. The acid solution is poured on iceand the 1-(l'-acetylaminopheny1)-3-methyl-5- pyrazolone separated in ayield of about 60-65 per cent is filtered with suction.

I claim:

1. Process of preparing l-acylamino-phenyl- 5-pyrazolones whichcomprises splitting oif the l-sulfonic acid group of1-acy1amino-phenyl-5-- pyrazolonel-sulfonic acids by treating theseCertificate of Correction Patent N 0. 2,322,907. June 29, 1943.

PAUL ZERVAS It is hereby certified that error appears in the printedspecification of the above numbered patent requiring correction asfollows: Page 2, second column, line 20, claim 4, for the word sulfonicread sulfuric; and that the said Letters Patent should be read with thiscorrection therein that the same may conform to the record of the casein the Patent Ofiice.

Signed and sealed this 22nd day of April, A. D. 1947.

LESLIE FRAZER,

First Assistant Oonunissz'oner of Patents.

